1. Field of the Invention
This invention relates, in general, to a method of metallizing materials, and particularly concerns a method of providing a substrate material with a coating of a hydrophilic composite material that can be electrolessly metal plated.
2. Prior Art
Various applications for metallizing materials are known. Some examples of these applications are as follows:
Metallized foams having macroscopic interconnected cells therein have been prepared in the prior art. A method of metallizing polyurethane foams, for example, is described in U.S. Pat. No. 3,549,505.
In the '505 patent, a reticular, electrically non-conductive cellular structure of polyurethane having a self-supporting three-dimensional network of inter-connected annulets with macroscopic inter-connected cells therein is coated with a conductive material followed by electroplating. Pyrolysis following the electroplating step is optional.
One method of coating the polyurethane with a conductive material according to the '505 patent is by electroless metal plating. When this method is utilized, the surface of the polyurethane is rendered hydrophilic by cleaning and etching processes. After the surface is rendered hydrophilic, the surface is electrolessly metal plated.
Other methods of producing metallized foams are known. Examples of such methods are described in U.S. Pat. Nos. 3,698,929 and 3,679,552.
A method of plating on plastics is described in U.S. Pat. No. 3,501,332. In this patent, organic polymer substrates are conditioned for electroless metal plating by impregnating the surface layer of the substrates with a metal diffused into the surface layer from a solution of a complex. The complex contains the metal in a zero-valent form dissolved in an organic solvent which has a dissolving or swelling action on the substrate.
Other methods of plating on plastics are known. Examples of such methods are described in U.S. Pat. Nos. 3,597,266; 3,632,388; 3,632,704; 3,661,538; and 3,716,394.